This invention relates to arrangements and methods for detecting objects from a motor vehicle.
There are many conventional arrangements for detecting objects which are located in the driving direction and in the driving area of a motor vehicle. In such arrangements the object distance and the angle to the object with respect to a central axis are determined.
British published application No. 2 279 841 discloses an object-detecting arrangement as a component of a speed control device. In this arrangement account is taken of driving on curves and, by automatic tracking and assessment of detected objects, dangerous objects are distinguished from harmless objects. For example, dangerous, rigid motionless barriers in the driving direction are distinguished from harmless vehicles driving ahead.
German Offenlegungsschrifft No. 43 41 689 discloses an anticollision radar system for motor vehicles which uses a distance sensor to determine an object distance as well as road curvature. This arrangement also uses a probability-determining device to identify vehicles driving ahead as distinct from fixed objects. Complicated measures are used especially when driving on curves, to determine probability distributions for detected conditions which are angularly displaced with respect to a central zone.
Another conventional obstacle-detecting arrangement for motor vehicles, disclosed in German Offenlegungsschrifft No. 44 18 122, involves similar considerations and takes account, for the straight-ahead direction of a motor vehicle, of main paths and substitute paths, laterally adjoining the main path, to appraise obstacles.
Furthermore, such an object-detecting arrangement is disclosed in German Patent No. 36 16 930 as a component of a distance controller which is used for automatic control of the distance from a vehicle driving ahead, in particular for convoy driving. In this case, a change in detected measuring beams is evaluated for the purpose of object detection and object appraisal.
In addition, a vehicle control system for controlling a vehicle with reference to a shape of a road is disclosed in German Offenlegungsschrifft No. 195 06 364. In that system, information relating to the road geometry is made available from a navigation device which provides map information from a plurality of coordinate points mapping the road.
In general, such conventional object-detecting arrangements include at least one distance sensor mounted on the vehicle, for example a radar or laser device, for emitting beams in different directions with respect to a central beam aligned in the longitudinal direction of the vehicle, as well as for receiving object-reflected measuring beams in a directionally selective fashion. The received measuring beams and their propagation delay are analyzed in an electronic evaluation system, and the object distance and the object angle, that is to say the position of an object relative to the vehicle, are determined therefrom.
Warning strategies for critical approaches for a vehicle to other objects and, in particular, for semi-automatic driving in conjunction with a distance controller, are only acceptable when the systems employed function at their best and are highly reliable and have only a low number of erroneous reports or faulty interventions.
In addition to precise object detection, an essential factor for effective functioning of such systems is an appraisal as to whether a critical, possibly dangerous object or a non-critical object is involved. In this case, objects outside a driving lane are to be appraised as non-critical in most cases.